NORTH BAY  -- North Bay counties are among the healthiest in the state, with Marin earning top honors in California and Sonoma and Napa among the top 15, according to a new report.

The County Health Rankings, recorded by the University of Wisconsin Population Health Institute and the Robert Wood Foundation, measure the overall health of nearly every county in all 50 states.

Sonoma County finished in  12th place in California, and is in the top 10 percent in several benchmarks of the study, including adult obesity, preventable hospital stays and the ratio of primary care providers to the population.

Napa finished in 14th place.  Solano ranked 31st, Mendocino at 33rd and Lake at 53rd.

Researchers used four measures to determine the level of overall health for California counties -- the rate of people dying before age 75; the percent of people who report being in fair or poor health; the numbers of days people report being in poor physical and mental health; and the rate of low-birth weight infants.

"We achieved this thanks to the commitment of our residents and the great work we do with our partners in the community," said Rita Scardaci, director of health services in Sonoma County. "Working together, we have again shown why Sonoma County is one of the healthiest places to live, work and play."

Sonoma County set goals through the Health Action partnership, a group that develops recommendations on local approaches to promote the health of the community while improve health care delivery. The latest results are an indication of its success, said Oscar Chavez, co-chair of Health Action.

Despite the county's high placement, there is room for improvement. For example, access to healthful foods continues to be a "low health measure within the rankings" despite the agricultural heritage of Sonoma County.

"We are working in several ways to address this issue, said Supervisor Valerie Brown. "We've launched iGROW through Health Action, and we are currently evaluating what county land might be available for local, sustainable, community-based farming and agricultural use."

The full rankings are available at www.countyhealthrankings.org.